Engine starter



June 29 3926., 1,50,758

M. B.!JACKSON ENGINE STARTER Filed Nov. 2o, 1924 INVENTEIR.

Patented June 29, 1926.

UNITED STATES PTEN T OFFICE.

ENGINE Application filed November This invention rel:ites to engine starters adapted to start internal combustion en ines, and more particularly to that type 1Il which a starter pinion is axially moved into and out of mesh with a gear on the engine, and my object is to provide a simple device of this character which will .be of few parts that may be cheaply manufactured and yet be durable and eflicient.

I attain my object by means of the constructions hereinafter described and illus trated in the accompanying drawings in Which- Fig. 1 is a side elevation of my device in its operative position;

Fig. 2 a sim1lar view in its operative posit1on;

F Fig. 3 a cross section on the line 33 in Fig. 4 a side elevation of a modified form of the device showing it in its operative position; and

Fig. 5 an end view of the same.

In the drawing like reference numerals indicate corresponding parts in the difi'erent figures. I

An electric motor 1 (only partly shown) is provided with an extended armature shaft 2 having an end 3 of reduced diameter. On this end is secured, in any suitable manner, -a collar 4 of substantially the same diameter as the main portion of the shaft 2. A pair of pins 5 and 5 are carried at opposite sides of the collar and these pins are so positioned relative to one another that they will engage the convolutions of a helical spring 6 freely disposed on the shaft and collar.

One end of the spring is bent laterally to form a shoulder or a hook 7 which is normally free of or unconnectcd with the shaft or collar but is adapted to enga e the pin 5 to form a rotary drive connection between the shaft and the spring. The other end of the spring is also bent to form a lateral projection 8 to which is connected a starter pinion 9. The pinion is loosely or freely carried on the shaft 2 and the connection between the projection 8 and the pinion is formed by passing the project-ion into a notch or oening 10 formed in the pinion. To retain t e projection in engagement with the pinion I secure, in any suitable manner,

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20, 1 924. Serial No. 751,000.

a disk 11 to the latter. This disk is provded with a finger 12 which is suitably shaped to engage the end convolution of the spring behind the pr0jection 8. Preferably the disk Will be a sheet metal stamping having. sufficient material to form the finger formed on its periphery.

The pinion is ada tod to mesh with a gear 13 connected with t e crankshaft of -an engine (not shown) the common practice being to secure -the gear to the engine flywheel. The entering ends of the teeth of the pinion are also tapered ofl as shown to facilitate the meshing of these teeth with the teeth of the flywheel gear.

-Assumin the starter mechahism is in its normal position as shown in Fig. 1 and it is desired to start the engine, the mode of operation is as follows. The motor 1 is energized which causesthe shaft 2 and thus the collar 4 and the pins 5 and 5 to rotate. As hereinbefore mentioned the spring 6 and the pinion 9 are freely carried on, the shaft 2 and the inertia of the former parts permite the shaft to rotate relative to them. The pins meshing with the convolutions of the s ring, axially feed or move the latter and t e pini0n towards the gear. When the pinion has been axially moved a suificient distance to fully mesh it with the gear, the hook 7 i's adapted to engage the pin 5, to form .a resilient .rotary drive connection between the starter motor and the pinion (see Fig. 2) which causes the crankshait of the engine to be revolved. Should the ends of the pinion teeth happen to engage the ends of the teethon the gear when they are being meshed the axial movement of the spring 6 would be tem'porarily stopped and the pins 5 and 5 would slightly cmpress the spring. and thus partially rotate the pinion to mesh it with the gear. It will be noted that the use oftwo pins will prevent distortion of the spring if the teeth on the pinion and gear jam as just described. Im mediately the pinion meshes with the gear the latter prevents any tendency of the spring to rotate with the shaft until the hook 7 engages the pin 5 To ensure this -engagement between the hook and the pin, a shoulder 15 is provided for engaging the pinion to limit its inward movement. The

The pinion is returned to its inperative position, when the en 'ne is started, in the following manner. -T e pins 5 and 5 are axially spaced, on the collar 4, a distance equal to one-half the normal pitch of the convolutions of the helical spring 6, the pin 5 being located closer to the outer end of the shaft. The speed of the flywheel gear when operated by the starter motor is less than its speed when the en ine is started so that the instant the engme starts, the speed of the starter pinion, relative to the starter sha-ft, is increased. This causes the hook 7 to be disengaged from the pin 5 and the convolutions of the spring to be threaded on the ins to move the pinion out of mesh with t e gear. An abutmeut 14 formed on or secured to the collar 4 is adapted to engage the hook 7 to limit its outward movement.

In the modified construction of my de vice as shown in Fig. 4 the collar 4 is omitted and the free end of the shaft is provided with a pin 14 to form an abutment to limit the outer movement of the hook 7. In this construction only one pin 5 is used for threading the spring which will work satisfactorily to mesh the pinion with the gear. When only one pin is used it is necessary to provide suflicient com pression in the spring to cause it to tend to thread itself on the pin. This is accomplished by locating the shoulder 15 relative to the pin 5 so that it is adapted to engage the ad;acent side of the mion 9 before the pin 5 engages the hoo 7' so that the s ring 6 will be slightly compressed before t e rotary drive connection is formed. From this it follows that when the hook 7 is disengaged from the pin 5, due to the engine being started as hereinbefore described, the end convolution of the spring, on which the hook is formed, will bear against the pin and ride past it to engage the outer side of the pin. The in is then positioned between the convolut1ons of the sprin and the rotary movement of the latter will cause it to be threaded on the pin to move the pinion out of mesh with the gear.

The convolutions ,of the spring are preferably rectangular in cross section to pro vide a maximum line of contact with the 1n. p Whetherthe shaft 2 and collar 4, shown in Figs. 1 and 2, or the shaft 2, as shown in Fi 4, be used, a substantially smooth and un roken surface will be rovided for the spring 6 to grip, which sur ace will not tend to distort the latter. As the pinion 9 is mounteddirectly on the shaft 2 it is possible to attain a low gear ratio between the pinion and the gear and at the same time have a shaft of ample cross section without using double reduction gearing to obtain these features.

The hereinbefore described arrangement and construction of the parts permits a 'short s ring 6 to be used which tends to lessen t e severity of a sudden shock due to a bustion engine provided with a gear for revolving the crank shaft thereof, of starter mechanism including a shaft; a pinion freely carried on the shaft and normally out of mesh with the gear; a helical Spring freely mounted on the shaft and having one end connected with the pinion and the other end provided with a hook normally unconnected with the shaft; a pin carried by the shaft for forming a threading engagement betweenthe letter and the spring whereby the pinion will be axially moved in opposite directions by the rotation of the shaft or the pinion relative to one another, the pin being also adapted to engage the hook to form a rotary drive connection between the shaft and the pinion; and an abutment supported inthe path of the pinion for engagement by the pinion to limit its axial movement in its gear meshing position, the pinion being adapted to engage the abutment before the pin engages the hook whereby the pin causes the spring to be compressed to assist its return movement.

2. The combination with an internal com bustion engine provided with a gear for revolving the crank shaft thereof, of starter mechanism includin a shaft; a pinion freebeing also ada ted to engage the hook to form a rotary rive connection between the shaft and the pinion; an abutment supported in the path of the pinion for engagement remote from the first mentione ebutment, by the pini0n to limit its axial movement the second mentioned abutment being adaptin its gear meshing position, the pinion beed to engage the hook to limit the movement m ing adapted to engege the shoulder before of the pimon in its unmeshed position.

the pin engages the h00k whereby the pin Signed at Toronto, Canada, this 15th day causes the spring to be compressed; and en of November, 1924. v abutment carried by the end of the shaft MAUNSELL B. JACKSON. 

